Automated computerized magnetic resonance detector and analyzer

ABSTRACT

The magnetic resonance signal analyzer allows to automatically generate a large variety of test signals including one or more frequencies. The test signals can be applied as electromagnetic fields or as currents to material under test. An electromagnetic or electrical response signal of the material under test be applied to the analyzer for processing to determine the response pattern of the material under test and then returned to the automatic controller of the frequency sources. The automatic controller determines the test signal with the most effective response for the particular matter under test.

This is a continuation-in-part application of my pending patentapplication 07/945,529, filed on Sept. 16, 1992, now U.S. Pat. No.5,317,265, issued May 31, 1994.

BACKGROUND OF THE INVENTION

A magnetic resonance analyzer offers new advantages in the field ofmaterial analysis. It has been shown that the applicability of such ananalyzer exceeds the range of tissue analysis and other medicalapplications. The magnetic resonance analyzer measures the degree andtype of response of a matter under test, and, by comparison withreference matter, it assists in recognizing deviations from a desiredresponse. This capability is enhanced by testing with resonance testpatterns which relate to the significant characteristics for theparticular matter under test as identified when determining theresonance frequencies.

The apparatus of the present invention relates to magnetic resonancetest instrumentation. It exposes reference material to anelectro-magnetic field and determines the resonance frequencies of thematerial exposed using a sequence of frequency patterns. The detectedresonance frequencies are be used to establish test patterns to be usedin subsequent operations for analyzing samples of the same type ofmaterial as and relative to the reference material.

SHORT DESCRIPTION OF THE INVENTION

The apparatus of the present invention includes the means forautomatically selecting a sequence of test patterns and means forgenerating a selected test pattern sequence. Two methods of subjecting amatter to the pattern signals are provided. A first method uses aninductive coil for generating an electromagnetic field under control oftest pattern signal and a sensor for electromagnetic fields for sensingthe response. The second method uses probes for electrical signals,causing electrical currents between input probes. Test probes are usedto sense currents at selected locations of the matter under test toevaluated the response of the matter under test to the applied testpatterns.

The sensed analog response signals are processed in a first analogsignal processing circuit and may generate a linear signal indicativefor deviations from an expectant result. A second analog processingcircuit performs a conversion from analog to digital representation ofthe response signal for evaluation in digital data processing means.Additional external equipment may be connected at suitable locations forevaluating a signal using commercially available equipment, such aspectrum analyzers etc.

The inductive coil for generating the electromagnetic fields and thesensor coil can be combined in various configuration for testingparticular matter. While both coils can be concentric in manyapplications, it has been found that in some applications speciallyshaped coils such as conically formed coils are more suitable to subjectthe matter under test to the electromagnetic field.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of the magnetic resonance analyzerand the automatic pattern control of the present invention

DESCRIPTION OF THE PREFERRED EMBODIMENT

The apparatus of the present invention can be used in various methods totest matter. In the following description of the preferred embodimentthe test is performed in a chamber in which the matter under test issubjected to an electromagnetic field generated by a primary coil. Asecondary coil is used to sense the sum of the test field and theresponse field. Primary and secondary coils may be concentric and thesecondary coil may be located inside the primary coil. Both coils may beelectromagnetically shielded to eliminate any influence from an externalelectromagnetic field.

The apparatus of the present invention has two signal frequencygenerators and a carrier frequency generator. The two frequencygenerators include the same type of major components: pattern selectmeans 10 and 50, respectively, pattern generator 12 and 52,respectively, and digital to analog converters 14 and 54 respectively.The inputs of the digital-to-analog converters receive a sequence ofbinary coded values which are converted into analog signals. Theresultant analog signals contain the frequencies which will cause aresonance response by the matter under test. The two analog signals aresupplied to modulator 16. The carrier frequency generator 70 provides aselected frequency signal. The output signal of generator 70 is fedthrough a wave shaper 72 and drives the carrier input 74 of modulator16. The output of modulator 16 provides the test pattern signal in whichthe carrier frequency pattern is modulated by the selected signalfrequency pattern. The frequency spectrum of the test patterns reachesfrom 3 Hz to 14 KHz. In FIG. 1 there is provided a separate output EPOUT 18 which makes the test signal available to external probes.

Using test chamber 20 of the apparatus the test pattern signal issupplied to a primary excitation coil 22, which generates theelectro-magnetic test field. The matter to be test 24 is placed insidecoil 22. A secondary coil 26 senses the resultant electromagnetic fieldinside test chamber 20. The electrical output signal of secondary coil26 includes a component from the test pattern field and a componentrepresenting the resonance signal of the matter under test responding tothe test field. A low-pass filter 28 eliminates all frequency componentsabove a certain frequency. The resultant filtered signal is comparedwith the electrical test pattern signal in comparator 30. The differencesignal is amplified in amplifier 36 and supplied to an electronic switch38. Switch 38 is provided to select either an external signal EP IN froman external device connected to line 34, or the filtered differentialsignal from amplifier 36. Switch 38 is controlled by a select signal online 40. The selected signal is amplified in amplifier 42 and providedto two evaluation channels. The first evaluation channel converts thereceived signal into a digital signal in D/A converter 44. The resultantdigital signal can be evaluated, processed, stored, modified or treatedotherwise in an processing device 46, such as a special or commonpurpose computer. The second evaluation channel includes a demodulator56, a voltage controlled oscillator 58 and an acoustic output device,such as a loudspeaker.

The magnetic resonance analyzer can generate a large variety of signalpatterns. For testing a particular matter the optimum test pattern hasto be determined which is significant to the particular matter itsevaluation. When testing a sample at a later time, a so determinedoptimum test pattern is selected and imposed on the sample under test.The resultant resonance spectrum can be compared with the expectedresultant test pattern and the user may draw a conclusions from thedifferences. Important features of the resultant signals are theresonance responses and the frequencies showing extraordinary peakemissions.

The resonance frequency analyzer of the present invention can beequipped with different types of primary and secondary coils dependingupon the material and its shape to be tested. In a similar fashion thetest signal can be supplied via output EP OUT 18 to input test probeswhich are inserted or attached to the material under test therebycausing an electrical current to flow between the input probes. Outputsense probes can be inserted or attached at other locations of thematerial under test to identify the reaction of the material under testto the test signal. The output sense probes are to be connected to inputEP IN 34. The detected signal is processed in the same manner as thesignal from the secondary coil of the test chamber.

To determine the resonance frequencies of a particular matter under testthe reference material is to be exposed to a plurality of test patternsand the resulting response is to be observed to determine which testpattern is to be used in testing against the reference matter.

In FIG. 1 an automatic controller 80 sequentially supplies input controlsignals to the frequency generators and thereby generates for each setof control signals a particular frequency pattern. For each of thesuccessive frequency patterns the detected response is provided byprocessing means 46 and transferred via line 81 to controller 80, whereit is recorded in a memory for further evaluation. The resultingresponse characteristics for the various frequency patterns are analyzedin controller 80 to determine which of the test patterns is to be usedfor testing material against their reference material. This analysis mayselect test patterns in accordance with the maximum amplitude of thedifference signal received for each of the test patterns. It may selecta test pattern in accordance with the strongest response signal sensedat he secondary coil, as represented by the largest difference signalover the frequency range of the applied test pattern.

Automatic controller S0 allows to scan a reference matter for mostsuitable frequency pattern, and to subject matter under test to asequence of test pattern for comparison with expected responses orstored responses of corresponding reference matter.

Automatic controller S0 may include selection means which in response toan input of the matter to be tested selects one or more of thepreviously determined test patterns for that particular matter andgenerates a test pattern sequence for the matter under test.

What is claimed is:
 1. An apparatus for generating a sequence ofelectro-magnetic test patterns for generating response signal of amatter under test comprising a sequence controller generating controlsignals including a first control signal and a second controlsignal;first means for generating a first electrical signal in responseto said first control signal; second means for generating a secondelectrical signal in response to said second control signal; modulatingmeans for modulating said second signal with said first signal andproviding a third electrical signal; first inductor means for generatingan electro-magnetic field controlled by said third electrical signal,said first inductor means being adapted to subject said matter undertest to said electro-magnetic field; said sequence controller includingmeans for providing a selected sequence of said first and second controlsignals for generating said sequence of selected electromagneticpatterns; second inductor means for sensing an electromagnetic field inclose proximity to said matter under test and providing a fourthelectrical signal, said fourth electrical signal being indicative of theelectromagnetic field generated by said first inductor means and theresonance magnetic field of said matter under test; means for comparingsaid third electrical signal with said fourth electrical signal andproviding an internal difference signal, said internal difference signalbeing indicative of the magnetic resonance characteristic of said matterunder test; means for analyzing said difference signal thereby providingan analyzed difference signal for every one of said test patterns.
 2. Anapparatus for generating a sequence of electro-magnetic test patternsfor generating response signals of a matter under test as claimed inclaim 1, said sequence controller further comprisingan input connectedto said means for analyzing for receiving said analyzed differencesignal, means for storing a plurality of said analyzed differencesignals, and means for evaluating said plurality of analyzed differencesignals for determining a most effective test pattern from said sequenceof test patterns.
 3. An apparatus for generating a sequence ofelectro-magnetic test patterns for generating response signals of amatter under test as claimed in claim 2, wherein said means forevaluating determine said most effective test pattern by determining thedifference signal with the highest amplitude.
 4. An apparatus forgenerating a sequence of electro-magnetic test patterns for generatingresponse signals of a matter under test as claimed in claim 2, whereinsaid means for evaluating determine said most effective test pattern bydetermining the difference signal relating with the strongest responseover the frequency range of the particular test pattern.